Method and apparatus for auto-focusing of an photographing device

ABSTRACT

An auto-focusing method of an electronic device is provided. The auto-focusing method includes collecting sensor information using a plurality of sensors of the electronic device when a camera of the electronic device is driven, determining at least one focusing sensor, from among the plurality of sensors, based on the collected sensor information, and focusing on a subject located in an image collected from the camera using the at least one determined focusing sensor.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims the benefit under 35 U.S.C. §119(a) of a Koreanpatent application filed on May 30, 2013 in the Korean IntellectualProperty Office and assigned Serial number 10-2013-0061782, the entiredisclosure of which is hereby incorporated by reference.

TECHNICAL FIELD

The present disclosure relates to an auto-focusing method and apparatusof a photographing device.

BACKGROUND

As communication technologies have developed, electronic devices, forexample, a portable terminal such as a smart phone, a tablet PersonalComputer (PC), a smart camera, a digital camera, and the like, havebecome widely utilized. A portable terminal are utilized in asignificantly wide field since the portable terminal is convenient touse and easy to carry.

Recently, a camera that provides a performance of high-definition andhigh-resolution has been contained in a portable terminal and thus, auser's desire for readily photographing a picture and/or a video hasbeen increased. Accordingly, an auto-focusing system has been providedthat automatically focuses on a subject without a special manipulationby a user of a camera or a camera application of a terminal.

Generally, an auto-focusing scheme supported in a photographing deviceincludes an infrared auto-focusing scheme, a contrast detectionauto-focusing scheme, or a phase difference detection auto-focusingscheme. When a significant amount of reflection occurs, such asreflection from a plane of glass, or when a distance to a subject isfar, the infrared auto-focusing scheme is difficult to execute forfocusing. The contrast detection auto-focusing scheme executes focusingbased on a contrast of a portion of a subject and thus, the contrastdetection auto-focusing is difficult to execute when a contrast does notexist in the subject. The phase difference detection auto-focusingscheme generates two images using a lens in a detection sensor andexecutes focusing using an interval between the images. The phasedifference detection auto-focusing scheme has difficulty in executingfocusing when light, such as sunlight or a reflected light, entersthrough a lens or when a subject is significantly small. Therefore,there is a need for a method of effectively executing focusing when aportable terminal equipped with a camera photographs a picture and/or avideo.

The above information is presented as background information only toassist with an understanding of the present disclosure. No determinationhas been made, and no assertion is made, as to whether any of the abovemight be applicable as prior art with regard to the present disclosure.

SUMMARY

Aspects of the present disclosure are to address at least theabove-mentioned problems and/or disadvantages and to provide at leastthe advantages described below. Accordingly, an aspect of the presentdisclosure is to provide a method and apparatus for auto-focusing of anelectronic device. An embodiment of the present disclosure provides amethod and apparatus for selecting focusing sensors optimized for anelectronic device in a respective environment and/or situation byutilizing various sensors supported in an electronic device, andexecuting auto-focusing using the selected sensors.

Another aspect of the present disclosure is to provide an electronicdevice equipped with a camera. Another embodiment of the presentdisclosure provides a method and apparatus for accurately and promptlyfocusing on a subject using various sensors, i.e., more than one sensor,supported in an electronic device, as opposed to using a single sensor.

In accordance with an aspect of the present disclosure, an auto-focusingmethod of a electronic device is provided. The method includescollecting sensor information using a plurality of sensors of theelectronic device when a camera is driven, determining at least onefocusing sensor, from among the plurality of sensors, based on thecollected sensor information, and focusing on a subject located in animage collected from the camera using the at least one determinedfocusing sensor.

In accordance with another aspect of the present disclosure, aphotographing device is provided. The photographing device includes acamera unit configured to collect an image including a subject, a sensorunit configured to collect photographing environment information, and tocollect a plurality of pieces of sensor information by processing thephotographing environment information, when the camera unit is driven,and a controller configured to collect sensor information using theplurality of sensors, to determine at least one focusing sensor, fromamong the plurality of sensors, based on the collected sensorinformation, and to control focusing on a subject located in the imagecollected from the camera unit using the at least one determinedfocusing sensor.

In accordance with another aspect of the present disclosure, anelectronic device equipped with a camera selects a set of optimizedsensors from among various sensors supported in the electronic devicebased on a camera photographing mode and an ambient environment, andautomatically focuses on a subject using the corresponding set ofsensors.

In accordance with another aspect of the present disclosure, focusing ona desired subject is promptly and accurately executed in an environmentwhere focusing is difficult, by utilizing sensors included in a terminalwithout separately changing a physical hardware.

Other aspects, advantages, and salient features of the disclosure willbecome apparent to those skilled in the art from the following detaileddescription, which, taken in conjunction with the annexed drawings,discloses various embodiments of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and advantages of certainembodiments of the present disclosure will be more apparent from thefollowing description taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 is a block diagram illustrating a configuration of an electronicdevice according to an embodiment of the present disclosure;

FIG. 2 is a flowchart illustrating an auto-focusing method of anelectronic device according to an embodiment of the present disclosure;

FIG. 3 is a flowchart illustrating an auto-focusing method according toan embodiment of the present disclosure;

FIG. 4 is a flowchart illustrating an auto-focusing method of anelectronic device according to an embodiment of the present disclosure;and

FIG. 5 illustrates diagrams for describing a candidate group of focusingsensors according to an embodiment of the present disclosure.

Throughout the drawings, like reference numerals will be understood torefer to like parts, components, and structures.

DETAILED DESCRIPTION

The following description with reference to the accompanying drawings isprovided to assist in a comprehensive understanding of variousembodiments of the present disclosure as defined by the claims and theirequivalents. It includes various specific details to assist in thatunderstanding but these are to be regarded as merely exemplary.Accordingly, those of ordinary skill in the art will recognize thatvarious changes and modifications of the various embodiments describedherein can be made without departing from the scope and spirit of thepresent disclosure. In addition, descriptions of well-known functionsand constructions may be omitted for clarity and conciseness.

The terms and words used in the following description and claims are notlimited to the bibliographical meanings, but, are merely used by theinventor to enable a clear and consistent understanding of the presentdisclosure. Accordingly, it should be apparent to those skilled in theart that the following description of various embodiments of the presentdisclosure is provided for illustration purpose only and not for thepurpose of limiting the present disclosure as defined by the appendedclaims and their equivalents.

It is to be understood that the singular forms “a,” “an,” and “the”include plural referents unless the context clearly dictates otherwise.Thus, for example, reference to “a component surface” includes referenceto one or more of such surfaces.

A method and apparatus according to the present disclosure may beapplied to a portable terminal. It is apparent that the portableterminal may be a portable terminal, a smart phone, a tablet PersonalComputer (PC), a hand-held PC, a Portable Multimedia Player (PMP), aPersonal Digital Assistant (PDA), a camera, a portable electronicdevice, and any other similar and/or suitable electronic device.Hereinafter, descriptions will be provided by assuming that anauto-focusing method and apparatus of an electronic device according tothe present disclosure is applied to a portable terminal.

FIG. 1 is a block diagram illustrating a configuration of an electronicdevice according to an embodiment of the present disclosure.

Referring to FIG. 1, an electronic device 100 according to the presentdisclosure is configured to include a display unit 110, an input unit120, a communication unit 130, an audio processing unit 140, a cameraunit 150, a sensor unit 160, a storage unit 170, and a controller 180.

The display unit 110 executes a function of outputting various functionscreens used for operating the electronic device 100. The display unit110 supports a function of visually providing a user with a menu, inputdata, function setting information, and other various information. Thedisplay unit 110 may be formed of a Liquid Crystal Display (LCD), anOrganic Light Emitting Diodes (OLED), an Active Matrix Organic LightEmitting Diodes (AMOLED), or the like, however, the display unit 110 isnot limited thereto and may be any other similar and/or suitable displaydevice.

The display unit 110 may display a photographed image screen obtainedthrough the camera unit 150 when the camera unit 150 is driven. Thedisplay unit 110 may display a User Interface (UI) for controlling acamera, together with the photographed image screen. For example, thedisplay unit 110 may display a UI for photographing mode settings,including a shutter speed, an open/close state of an aperture, a whitebalance, an International Organization of Standardization (ISO) standardfor sensitivity to light, application of a filter, and the like, ashutter menu, a picture/video mode switching menu, and a zooming in/outmenu, together with the photographed image screen. Also, the displayunit 110 of the present disclosure may display, on a photographed imagescreen, a focus mark that defines a focus area for executing focusingwith respect to a photographed image, under a control of the controller180.

The input unit 120 senses a user input, and executes a function oftransferring an input signal corresponding to the user input to thecontroller 180. The input unit 120 may be configured to include any ofthe following elements which are not shown in FIG. 1, such as a key pad,a dome switch, a capacitive and/or resistive touch pad, a jog wheel, ajog switch, a finger mouse, a wheel, a hard key, and the like. Also, theinput unit 120 may be configured to include any of the followingelements which are not shown in FIG. 1, such as a touch sensor, aproximity sensor, an electromagnetic sensor, a pressure sensor, and thelike. The input unit 120 may be provided as a virtual touch pad, when atouch panel of the electronic device 100 is provided in a form of a fulltouch screen and/or a partial touch screen. Also, when a touch panel isincluded in the display unit 110, the display unit 110 may operate asthe input unit 120. In this case, an input signal for operating aterminal may be generated through the touch panel.

The input unit 120 according to the present disclosure may sense a userinput for setting a photographing mode of the camera unit 150, a userinput for requesting focusing, and a user input for requesting beginningof photographing.

The communication unit 130 executes communication by transmitting andreceiving a wireless signal to/from a location external to thecommunication unit 130. The communication unit 130 according to thepresent disclosure may be configured to include a mobile communicationmodule 131 and a Global Positioning Service (GPS) receiving module 132,but the communication unit 130 is not limited thereto and may includeany other similar and/or suitable communication module for wired and/orwireless communication. For example, the communication unit may beconfigured to further include a wireless Internet module for wirelessInternet connection and a satellite communication module.

The mobile communication module 131 transmits and receives a wirelesssignal to/from a base station, a server, and the like. The wirelesssignal may include data provided in various forms as a voice callsignal, a video call signal, and a text/multimedia message istransmitted and received. The GPS receiving module 132 receives a GPSsatellite signal from a GPS satellite, and transfers the received GPSsatellite signal to the controller 180, under a control of thecontroller 180. The controller 180 may calculate location informationassociated with a location where the terminal 100 is currently located,using a GPS satellite signal.

The audio processing unit 140 may be formed of a coder/decoder (codec),and the codec may be formed of a data codec, that processes packet dataand the like, and an audio codec, that processes an audio signal such asa voice and the like. The audio processing unit 140 converts a digitalaudio signal into an analog audio signal through the audio codec andplays back the analog audio signal through a Speaker (SPK), and convertsan analog audio signal input through a Microphone (MIC) into a digitalaudio signal through the audio codec.

In the present disclosure, the audio processing unit 140 supports asensor function that collects and measures an ambient sound. Forexample, when the audio processing unit 140 collects an ambient audiosignal through a MIC when the camera unit 150 is driven, the audioprocessing unit 140 may transfer the collected audio signal to thecontroller 180. The controller 180 determines whether a voice signalexists among the collected audio signal, and when it is determined thata voice signal exists, the controller 180 may measure a direction and adistance to a subject corresponding to and/or generating the voicesignal using a triangulation scheme.

The camera unit 150 is driven under a control of the controller 180, andexecutes a function of collecting an image by photographing a subject.The camera unit 150 may be activated based on a signal generated fromthe input unit 120, and may collect an image. The camera unit 150 may beconfigured to include at least one of the following elements, which arenot shown in FIG. 1, such as a camera sensor, an image signal processorthat converts an optical signal into an electric signal, a digitalsignal processor that executes image processing, such as scaling,removing noise, Red Green Blue (RGB) signal converting, or the like, ofa video signal output from the image signal processor so as to displaythe video signal, and the like. Here, the camera sensor may be at leastone of a Charge-Coupled Device (CCD) sensor, a Complementary Metal-OxideSemiconductor (CMOS) sensor, or any other similar and/or suitable cameraand/or image sensor. The camera unit 150 may be configured to include afirst camera, which may be a front side camera, for photographing apicture in a self-mode, and a second camera, which may be a back sidecamera, for photographing a subject located in front of a user. Thecontroller 180 may control the display unit 110 so as to display animage collected through the camera unit 150 as a preview image.

Also, as a request for execution of photographing is generated, thecontroller 180 photographs an image collected through the camera unit150 at a point in time corresponding to the generation of the requestfor execution of photographing, and the camera unit 150 generates animage. The generated image may be temporarily and/or permanently storedin the storage unit 170. The sensor unit 160 senses and collectsinformation on a change in a user input and a change in an ambientenvironment, and executes a function of transferring the information tothe controller 180. In the present disclosure, the sensor unit 160collects senor information associated with a change in a magnetic field,gravity, a pressure, a temperature, humidity, a quantity of light, asound, and the like, so as to determine a current state of theelectronic device 100.

The sensor unit 160 may be configured to include various sensors thatare not shown in FIG. 1, for example, a touch sensor that recognizes atouch input, a proximity sensor that senses a proximity of an externalobject or a user input instrument, a distance measuring sensor, an imagesensor that collects an image, a motion recognition sensor thatrecognizes a motion and a movement in a three-Dimensional (3D) space, adirection sensor that senses a direction and the like, an accelerationsensor that detects a moving speed, and the like, and any other similarand/or suitable sensor. The electronic device 100 according to thepresent disclosure may not be limited by a configuration of the sensorunit 160, and a MIC that collects an audio signal and/or a communicationmodule may also execute a function of the sensor unit 160.

Also, in the electronic device 100 according to the present disclosure,a sensing processing module 171 may detect feature information throughcollected sensor information, such as an eye pattern recognitionalgorithm that may recognize a direction at which a user gazes, a soundlocalization algorithm, a symbol recognition algorithm, a facialrecognition algorithm, an edge detection algorithm, and the like.

The sensor unit 160 according to the present disclosure may be activatedto collect ambient environment information and to transfer the collectedinformation to the controller 180, under a control of the controller180, when the camera unit 150 is driven. The controller 180 maydetermine at least one focusing sensor, or in other words, thecontroller 180 may select at least one sensor to be the at least onefocusing sensor, based on sensor information and a photographing mode.

The storage unit 170 stores various data and the like generated in theelectronic device 100, in addition to an Operating System (OS) of theelectronic device 100 and various applications, which may be referred toas apps. The data may include data generated from execution of anapplication, which may be referred to as an app, of the electronicdevice 100, and all types of storable data that may be generated using aportable terminal and/or storable data that may be received from anoutside source, for example, an external server, another portableterminal, a personal computer, or any other similar and/or suitableoutside and/or external source. The storage unit 170 may store a userinterface provided in the electronic device 100 and various settinginformation associated with processing functions of a portable terminal.In the storage unit 170, programs and/or commands for the electronicdevice 100 may be stored. The controller 180 may execute the programsand/or commands stored in the storage unit 170.

The storage unit 170 may include at least one type of storage medium,which may be a non-volatile computer readable storage medium, from amonga flash memory type, a hard disk type, a multimedia card micro type, acard type of memory, for example, a Secure Digital (SD) memory, an xDmemory, or the like, a Random Access Memory (RAM), a Static RandomAccess Memory (SRAM), a Read-Only Memory (ROM), an Electrically ErasableProgrammable Read-Only Memory (EEPROM), a Programmable Read-Only Memory(PROM), a magnetic memory, a magnetic disk, an optical disk, or anyother similar and/or suitable storage medium.

According to an embodiment of the present disclosure, the storage unit170 may temporarily and/or permanently store an image collected throughthe camera unit 150. Also, the storage unit 170 may temporarily and/orpermanently store a picture and/or a video generated in response to arequest for execution of photographing. The storage unit 170 may storeinformation associated with a picture and/or information to beassociated with the picture, for example, time information associatedwith a time where the picture is photographed, location information,information associated with a mode set for a camera when the picture isphotographed, pixel information, and the like.

The storage unit 170 according to the present disclosure may beconfigured to include a plurality, i.e., more than one of the sensingprocessing module 171 that may detect feature information throughcollected sensor information, such as an eye pattern recognitionalgorithm that may recognize a direction in which a user gazes, a soundlocalization algorithm, a symbol recognition algorithm, a facialrecognition algorithm, an edge detection algorithm, and the like.

The controller 180 controls general operations of the electronic device100, controls a signal flow among internal components of the electronicdevice 100, and executes a function of processing data. The controller180 may control supplying of power from a battery to internal componentsof the electronic device 100. When power is supplied, the controller 180controls a boot process of the electronic device 100, and executesvarious application programs stored in a program area for executing afunction of the electronic device 100, based on settings of a user.

In the present disclosure, the controller 180 may be configured toinclude a sensor information collecting unit 181, a sensor determiningunit 182, and a focusing unit 183.

The sensor information collecting unit 181 is connected with the sensorunit 160, the communication unit 130, the audio processing unit 140, thestorage unit 170, and the camera unit 150, and may activate a pluralityof sensors supported in a terminal, such as the electronic device 100,when the camera unit 150 is driven, so as to collect sensor informationof the sensors. It is preferable that the sensor information includesfirst sensor information that may be collected through the camera unit150, a MIC, the communication unit 130, the sensor unit 160, and thelike, and second sensor information that may be collected through thesensing processing module 171 based on the collected first sensorinformation, such as face detection, voice detection, outlineinformation, and the like. Here, the collected sensor information may bedifferent based on a type of an electronic device and an ambientenvironment.

The sensor determining unit 182 may determine at least one auto-focusingsensor based on sensor information collected through the sensorinformation collecting unit 181 and a photographing mode. Theauto-focusing sensor may include at least a direction measuring sensorthat determines a direction of a subject and a distance measuring sensorthat determines a distance to a subject. The sensor determining unit 182may calculate an accuracy point of sensor information for each collectedsensor and a weight associated with a photographing mode and maydetermine a sensor having the highest value to be an auto-focusingsensor, however, the present disclosure is not limited thereto and othersimilar and/or suitable methods of determining the auto-focusing sensormay be used.

The focusing unit 183 focuses on a subject by using a directionmeasuring sensor (not shown) and a distance measuring sensor (not shown)determined by the sensor determining unit 180. For example, the focusingunit 183 may determine a direction in which the camera unit 150 aims, orin other words, a direction in which the camera unit 150 is pointed,using the distance measuring sensor, and may determine a direction of asubject based on the direction in which the camera 150 aims. Thefocusing unit 183 may set a Region Of Interest (ROI) for focusing on adirection of a subject. The focusing unit 183 may execute focusing bydetermining a distance from the set ROI to the subject, using thedistance measuring sensor.

Hereinafter, detailed functions of the controller will be described withreference to FIGS. 2 through 4.

With the tendency of digital devices for convergence, there are manyvarious modifications of a digital device to enumerate. The electronicdevice 100 may be configured by omitting or replacing predeterminedcomponents in the described configuration based on a type of the deviceprovided.

FIG. 2 is a flowchart illustrating an auto-focusing method of anelectronic device according to an embodiment of the present disclosure.

Referring to FIG. 2, the electronic device 100 detects a user input fordriving a camera, such as the camera unit 150, and/or driving a cameraapplication in operation 210. In operation 220, the electronic device100 activates, i.e. turns on, the camera unit 150. In this process, theelectronic device 100 may display a preview image collected through thecamera unit 150 in the display unit 110. In operation 230, when thecamera unit 150 is activated, the electronic device 100 collects aplurality of pieces of sensor information using a configurationsupported in the electronic device 100 and sensing programs. Here, it ispreferable that the sensor information includes sensor informationcollected through the camera unit 150, a MIC, the communication unit130, the sensor unit 160, and the like, and also includes sensorinformation collected through the sensing processing module 171 based oninformation collected through the components, such as face detection,voice detection, edge detection, for example, outline information,symbol recognition, direction recognition, location measurement,movement recognition, motion recognition, and the like.

For example, when the camera unit 150 is activated, the electronicdevice 100 may collect ambient luminance information, that is,information associated with a quantity of light, through a sensor thatsenses light, audio information collected through a MIC, locationinformation of a terminal, and the like. Also, the electronic device 100may collect sensor information needed for using an eye patternrecognition algorithm, a sound localization algorithm, a symbolrecognition algorithm, a face recognition algorithm, an edge detectionalgorithm, and any other similar and/or suitable algorithm used by theelectronic device 100.

In operation 240, the electronic device 100 analyzes the collectedsensing information and calculates accuracies and weights of sensors, orin other words, calculates an accuracy point and a weight of eachsensor. Here, the accuracy point indicates a numerical value calculatedbased on ambient environment information, and the weight indicates anumerical value assigned for each sensor based on a photographing modeof a photographing device.

For example, when a photographing environment is dark, an accuracy ofsensor information collected through an image sensor may be low.Further, since the accuracy of the image sensor is low, there may bedifficulty in collecting sensor information through a face recognitionalgorithm and an eye pattern recognition algorithm that uses imagesensor information. In this case, the electronic device 100 maycalculate accuracies and weights of other sensors, excluding sensorsthat use an image sensor, to be relatively higher.

In operation 250, the electronic device 100 may determine at least onesensor for focusing, or, in other words, may determine at least onefocusing sensor optimized for a photographing environment and aphotographing mode based on accuracies and weights of sensors. Here, theat least one focusing sensors may include at least one of a directionmeasuring sensor (not shown) for measuring a direction of a subject anda distance measuring sensor (not shown). Here, the photographing modemay include a still image photographing mode, such as a picturephotographing mode, and a video photographing mode. The directionmeasuring sensor and the distance measuring sensor may be different fromeach other or may be identical to each other, and this may not belimited thereto.

The photographing mode of the electronic device 100 may be a picturephotographing mode as opposed to a video photographing mode, and anambient environment and a weight of each sensor is different for eachphotographing mode and thus, sensors determined for measuring a soundand a direction for each photographing mode may be different from avideo photographing mode.

For example, when a user photographs a video with an electronic devicethat is not equipped with a communication modem in an environment whereit is dark and free of noise, the electronic device determines a stereomicrophone sensor as a direction measuring sensor and also determines astereo microphone sensor as a distance measuring sensor since a quantityof light is insufficient due to the dark environment and the lack ofnoise. In a case where the photographing mode of the camera is the videophotographing mode and thus, there is a high probability that a subjectgenerally exists in a direction from which a sound is heard, and thus,it may be construed to be a case in which a weight of a microphonesensor is calculated to be high in a photographing mode.

Here, the stereo microphone sensor may calculate a direction and adistance to the subject using a triangulation scheme. Also, when a userphotographs a still image, for example, a picture, with an electronicdevice that is not equipped with a communication modem in an environmentwhere it is dark and free of noise, the electronic device may determinea symbol recognition algorithm to be a distance measuring sensor. Forexample, in a video photographing mode, an image of a supplementarylight that is shone may be included in an image and thus, there may bedifficulty in using the supplementary light. However, in a still image,a subject desired to be photographed may be different from a subjectthat transfers a voice, and it may be possible that an electronic deviceshines a predetermined image pattern on the subject through thesupplementary light. Therefore, in the sill image photographing mode,using the supplementary light is more useful for executing focusing andthus, in the still image photographing mode, a symbol recognition sensormay be selected to be a focusing sensor for measuring a distance and astereo microphone sensor may be determined to be a focusing sensor formeasuring a direction. An algorithm for measuring a distance to thesubject using the symbol recognition sensor may measure a direction ofthe subject through a microphone sensor first, may set the correspondingdirection to be an ROI, and may shine the supplementary light to thecorresponding direction. Subsequently, the electronic device may beaware of a size of a symbol, and a size of the subject is inverselyproportional to a distance between the electronic device and the subjectand thus, the electronic device may measure the distance to the subjectusing the same.

In operation 260, the electronic device 100 focuses on the subject usingthe at least one determined auto-focusing sensor, or in other words, theelectronic device 100 executes focusing by measuring a distance to and adirection of a subject using the at least one determined sensor.Hereinafter, a focusing method will be described in detail withreference to FIG. 3.

FIG. 3 is a flowchart illustrating an auto-focusing method according toan embodiment of the present disclosure.

Referring to FIG. 3, the electronic device 100 determines a referencesubject in an image collected through a camera, such as the camera unit150, in operation 310. Here, the subject may be construed to be a targetfor which a decision associated with focusing is made, or in otherwords, the determined reference subject in an image may be used as atarget corresponding to the auto-focusing method. For example, theelectronic device 100 may use various decision algorithms to decide thereference subject. For example, the electronic device 100 may use analgorithm that extracts an outline of a subject using a grade of abrightness, a color, a chroma, and the like and a continuity of thegrade. In this example, the subject may include a subject having a clearoutline and a subject that does not have a clearly outstanding outline,such as a landscape. When the subject having a clear outline exists, theelectronic device 100 may determine the subject having the clear outlineto be the reference subject which is used as a reference for focusing.

Alternatively, the electronic device 100 may use an algorithm thatcalculates a similarity of a brightness, a color, a chroma, and thelike, and extracts only an area having a similar characteristic to be asubject. Also, the electronic device 100 may detect a facial area froman image as a subject and may recognize the subject. The face detectionoperation may be executed together with an auto facial recognitionfunction of a camera. When the electronic device 100 fails to recognizeor extract a subject in an image, the electronic device 100 maydetermine a central area of the image to be the reference subject whichis a target for which a decision associated with focusing is made.

In operation 320, the electronic device 100 determines the subject to bethe target for which a decision associated with focusing is made, anddetermines and/or measures a direction of the subject using thedirection measuring sensor determined in operation 250 of FIG. 2.

For example, when the electronic device 100 is equipped with a stereomicrophone, a direction and/or a distance to the subject may bedetermined based on a triangulation scheme using the sound localizationalgorithm. Alternatively, when the subject is a person and the person isequipped with a terminal including a communication device, theelectronic device 100 may recognize location information of the terminalof the person corresponding to the subject, so as to determine adirection of the subject.

In operation 330, the electronic device 100 sets an ROI for focusing,that is, the electronic device 100 sets a focusing area to a selecteddirection where the subject exists, when the direction of the subject isdetermined. Here, the electronic device 100 may output a focus markindicating the set ROI on a predetermined position of a preview image.Here, the electronic device 100 executes graphics processing, withrespect to a focus mark, differently based on whether focusing iscompleted, and outputs a state in which focusing is completed and astate in which focusing is incomplete to be distinguished. The ROIcorresponds to an area that provides a reference for refocusing and anarea that provides a reference for sensing a movement of a subject.

In operation 340, the electronic device 100 may determine a distancefrom the ROI to the subject using the distance measuring sensordetermined in operation 250 of FIG. 2, or in other words, the electronicdevice 100 may measure a distance to the subject using the distancemeasuring sensor, so as to complete an operation of focusing on thesubject.

For example, the electronic device 100 may measure a time that it takesfor an infrared light and/or an ultrasonic wave emitted from theelectronic device 100 to return back through reflection from thesubject, so as to determine the distance to the subject. Alternatively,when the subject is recognized through the facial recognition, theelectronic device 100 may determine the distance to the subject based ona size of the subject in an image, a ratio of the subject to the image,and the like. Also, the electronic device 100 may measure the distanceto the subject using a symbol recognition sensor. In this case, theelectronic device 100 may measure a direction of the subject through amicrophone sensor, may set the corresponding direction to be an ROI, andmay shine a supplementary light in the corresponding direction.Subsequently, the electronic device 100 may be aware of a size of asymbol, and a size of the subject is inversely proportional to adistance between the electronic device 100 and the subject and thus, theelectronic device 100 may measure the distance to the subject using thesame.

FIG. 4 is a flowchart illustrating an auto-focusing method of anelectronic device according to another embodiment of the presentdisclosure.

Referring to FIG. 4, in operation 410, the camera unit 150 is drivenaccording to a user input and/or a predetermined schedule and theelectronic device 100 enters a picture photographing mode. Theelectronic device 100 according to the present disclosure may support ahalf-press shutter function. In this process, the electronic device 100may display a preview image collected through the camera unit 150 in thedisplay unit 110.

In operation 420, when the camera unit 150 is activated, the electronicdevice 100 collects a plurality of pieces of sensor information using aconfiguration supported in the electronic device 100 and sensingprograms. Subsequently, the electronic device 100 analyzes the collectedsensing information and calculates an accuracy point and a weight ofeach sensor. Here, the accuracy point indicates a numerical valuecalculated based on ambient environment information, and the weightindicates a numerical value assigned for each sensor based on aphotographing mode of the electronic device 100.

In operation 430, the electronic device 100 may determine at least onefocusing sensor optimized for a photographing environment and aphotographing mode based on accuracy points and weights of sensors, orin other words, the electronic device 100 may determine at least onesensor for focusing based on sensor information. Here, the focusingsensors include at least a direction measuring sensor for measuring adirection of a subject and a distance measuring sensor. The directionmeasuring sensor and the distance measuring sensor may be different fromeach other and may be identical to each other, however, the presentdisclosure is not limited thereto.

In operation 440, the electronic device 100 detects a first user inputthat requests execution of the half-press shutter function. Here, thefirst user input may be an input of pressing a shutter button or ahalf-pressing of the shutter button, as supported in the electronicdevice 100, with a first pressure. In operation 450, the electronicdevice 100 executes focusing by determining and/or measuring a directionand a distance to the subject using at least one determined sensor,which may be the determined focusing sensor, in response to the firstuser input. The electronic device 100 may output information associatedwith focusing to the display unit 110 as a preview image screen. When afocusing operation is completed, the electronic device 100 may beoperated in a focusing lock state (AF Lock) while a user inputs ahalf-press shutter button. In this example, the user may determinewhether focusing on the subject is executed, through a preview screen.

In operation 460, the electronic device 100 may detect a second userinput that requests photographing a picture. Here, the second user inputmay be an input of pressing a shutter button with a second pressurewhich is relatively greater than the first pressure. In operation 470,the electronic device 100 executes photographing in order to photographa picture of the subject in response to the second user input.

FIG. 5 illustrates diagrams for describing a candidate group of focusingsensors according to an embodiment of the present disclosure.

Referring to FIG. 5, an electronic device according to the presentdisclosure calculates an accuracy of a sensor based on a change of aphotographing environment, assigns a weight based on a photographingmode, and supports a function of determining a focusing sensor based ona photographing environment, so as to select a sensor optimized for thephotographing environment when a camera executes photographing.

For example, the diagram 501 is a table including accuracies of sensorsfor selecting a subject direction measuring sensor from among focusingsensors, and “a line” included in the table of FIG. 5 may be construedto be an accuracy point of each sensor based on a photographingenvironment. The electronic device 100 may select, as a candidate group,sensors that are capable of measuring a direction from among sensorssupported in the device. For example, a candidate group of directionmeasuring sensors may include an image sensor, a microphone, an eyerecognition detection processing module, a facial recognition processingmodule, a communication module, and the like. The direction measuringsensors may collect sensor information based on a change of anenvironment, such as a change in illumination, ambient noise, and acommunication signal. The electronic device 100 calculates a point basedon sensor measurement accuracy, which is based on the collected sensorinformation.

For example, as illustrated in the diagram 501, an eye patternrecognition algorithm and a facial recognition algorithm may be operatedbased on the information collected through the image sensor, and anaccuracy of measured sensor information may be deteriorated based on achange in illumination, that is, when illumination is significantly highor low. That is, when ambient illumination is significantly high or low,the electronic device 100 sets an accuracy point of image sensorinformation to “0”, and when illumination is appropriate, the electronicdevice 100 sets an accuracy point of the image sensor to be the highestpoint. Also, when provided with a communication modem and a GlobalPositioning System (GPS) receiving module sensors that may not beaffected by a change of illumination, the electronic device 100 mayreflect them and may set the accuracy point to a constant valueirrespective of a change of an environment.

Subsequently, the electronic device 100 calculates a weight value basedon a photographing mode for each sensor. The weight value based on thephotographing mode may indicate a value in an ideal environment, forexample, a value in a case where photographing is executed in a state inwhich all of the sensors supported in a device are available for use.The electronic device 100 may select, as a direction measuring sensor, asensor having the highest point obtained by multiplying an accuracypoint and a weight value.

The electronic device 100 may select a focusing sensor using thefollowing Equation 1.

MAX(point)_(i=1) ^(n) X _(e) W _(m)  Equation 1

Here, X_(e) denotes an accuracy point of a sensor in a photographingenvironment, W_(m) denotes a weight value of a corresponding sensorbased on a photographing mode, and n denotes a total number of sensorssupported in an electronic device.

For example, a diagram 502 is a table including accuracies of sensorsfor selecting a subject distance measuring sensor from among focusingsensors, and “a line” included in the table of FIG. 5 may be construedto be an accuracy of each sensor based on a photographing environment.It may be recognized that a candidate group of distance measuringsensors and a candidate group of direction measuring sensors aredetermined to be different through comparing the diagram 501 and thediagram 502.

For example, a gaze detection sensor may be appropriate for measuring adirection of a subject, whereas it may be inappropriate for measuring adistance. Conversely, a symbol recognition sensor may be appropriate formeasuring a distance to a subject, whereas it may be inappropriate formeasuring a direction of the subject. Therefore, a weight of each sensorin an algorithm for selecting distance measuring sensors may beconfigured to be different from a case of calculating a weight of adirection measuring sensor. As described in the diagram 501, theelectronic device 100 may calculate accuracies and weights of distancemeasuring sensors, and may select a sensor having the highest pointobtained by multiplying an accuracy point and a weight value to be adistance measuring sensor.

A description will be made through a concrete example. When a terminal,such as the electronic device 100, is operated in a video photographingmode, the terminal selects a communication modem as a directionmeasuring sensor, and selects an image sensor as a distance measuringsensor. For example, when a subject is equipped with a portable terminalincluding a communication device, such as the electronic device 100including the communication unit 130, a direction of photographing thesubject may be sensed by recognizing a location of the portable terminalof the subject. Also, the terminal measures a signal of the portableterminal of the subject so as to sense a direction, and measures adistance using an image sensor since a quantity of light is sufficientand thus, a time for focusing may be reduced. Conversely, when thesubject is not a person and/or does not have the portable terminalequipped with a communication device, the direction of the subject maybe sensed by detecting a gaze of a person who executes photographingthrough an image sensor. Also, when the distance to the subject is far,the distance may be measured using a GPS receiving unit and MAPinformation associated with a neighboring area.

Conversely, when the terminal is operated in a picture photographingmode, a quantity of light is sufficient and thus, a communication modemand an image sensor may be determined to be focusing sensors in the samemanner as the video photographing mode. When the subject is a person andis equipped with the portable terminal including the communicationmodem, the terminal senses a direction of the subject and sets an ROI ina preview mode, and calculates a distance to the subject using the imagesensor at a point in time when a user half-presses a shutter button soas to focus on the subject.

As described above, according to the present disclosure, at least onefocusing sensor is determined according to a photographing environment,a characteristic of a sensor, and a photographing mode, and focusing ona subject may be executed using the determined focusing sensors. Thatis, according to the present disclosure, focusing is executed byvariously changing focusing sensors based on sensor information ofsensors and thus, focusing on a desired subject may be promptly andaccurately executed in an environment where focusing is difficult.

While the present disclosure has been described with reference tovarious embodiments thereof, it will be understood by those skilled inthe art that various changes in form and details may be made thereinwithout departing from the spirit and scope of the present disclosure asdefined by the appended claims and their equivalents.

What is claimed is:
 1. An auto-focusing method of an electronic device,the method comprising: collecting sensor information using a pluralityof sensors of the electronic device when a camera of the electronicdevice is driven; determining at least one focusing sensor, from amongthe plurality of sensors, based on the collected sensor information; andfocusing on a subject located in an image collected from the camerausing the at least one determined focusing sensor.
 2. The method ofclaim 1, wherein the determining of the at least one focusing sensorcomprises: calculating an accuracy point and a weight of sensorinformation respectively for each of the plurality of sensors of whichthe collected sensor information is collected; and determining, as theat least one focusing sensor, a sensor, from among the plurality ofsensors, having a highest value based on the calculated accuracy pointand weight.
 3. The method of claim 2, wherein the determining of the atleast one focusing sensor comprises: determining a direction measuringsensor that determines a direction of a subject; and determining adistance measuring sensor that determines a distance to a subject. 4.The method of claim 3, wherein the focusing on the subject comprises:determining a reference subject in the image collected from the camera;determining a direction of the reference subject using the directionmeasuring sensor; setting a Region Of Interest (ROI) for executingre-focusing with respect to the direction of the reference subject; andexecuting focusing by determining a distance from the ROI to thereference subject using the distance measuring sensor.
 5. The method ofclaim 2, wherein the calculating of the accuracy point and the weight ofthe sensor information comprises: calculating the accuracy point of thecollected sensor information according to photographing environmentinformation; and calculating the weight according to a photographingmode of the camera.
 6. The method of claim 1, wherein the sensorinformation comprises at least one first sensor information that iscollected from among a quantity of light, an image, a speed, a sound,and a location, and at least one second sensor information that iscollected, from among motion recognition, movement recognition, facialrecognition, voice detection, edge detection, symbol recognition,direction recognition, and location measurement, by processing the firstsensor information.
 7. The method of claim 1, wherein the focusing onthe subject comprises executing focusing when both the photographingdevice supports a half-press shutter function and a user input thatrequests execution of the half-press shutter function is detected. 8.The method of claim 1, wherein the plurality of sensors includes atleast one of a touch sensor that recognizes a touch input, a proximitysensor that senses a proximity of an external object, a distancemeasuring sensor, an image sensor that collects an image, a motionrecognition sensor that recognizes a motion and a movement in athree-Dimensional (3D) space, a direction sensor that senses a directionand the like, and an acceleration sensor that detects a moving speed. 9.The method of claim 1, further comprising detecting feature informationfrom among the collected sensor information, wherein the featureinformation includes at least one of an eye pattern recognitioninformation indicating a direction at which a user gazes, soundlocalization information, symbol recognition information, facialrecognition information, and edge detection information.
 10. Aelectronic device comprising: a camera unit configured to collect animage including a subject; a sensor unit configured to collectphotographing environment information, and to collect a plurality ofpieces of sensor information by processing the photographing environmentinformation when the camera unit is driven; and a controller configuredto collect sensor information using the plurality of sensors, todetermine at least one focusing sensor, from among the plurality ofsensors, based on the collected sensor information, and to controlfocusing on a subject located in the image collected from the cameraunit using the at least one determined focusing sensor.
 11. Theelectronic device of claim 10, wherein the controller is configured tocalculate an accuracy point and a weight of sensor informationrespectively for each of the plurality of sensors of which the collectedsensor information is collected, and wherein the controller isconfigured to determine as the at least one focusing sensor, a sensor,from among the plurality of sensors, having a highest value based on thecalculated accuracy point and weight.
 12. The electronic device of claim10, wherein the controller is configured to determine a referencesubject in the image collected from the camera unit, wherein thecontroller is configured to determine a direction of the referencesubject using a direction measuring sensor, wherein the controller isconfigured to set a Region Of Interest (ROI) for executing re-focusingwith respect to the direction of the reference subject, and wherein thecontroller is configured to execute focusing by determining a distancefrom the ROI to the reference subject using a distance measuring sensor.13. The electronic device of claim 10, wherein the controller isconfigured to calculate an accuracy point of the collected sensorinformation according to photographing environment information, andwherein the controller is configured to calculate a weight according toa photographing mode of the camera unit.
 14. The electronic device ofclaim 10, wherein the sensor information comprises at least one firstsensor information that is collected from among a quantity of light, animage, a speed, a sound, and a location, and at least one second sensorinformation that is collected from among motion recognition, movementrecognition, facial recognition, voice detection, edge detection, symbolrecognition, direction recognition, and location measurement byprocessing the first sensor information.
 15. The electronic device ofclaim 10, wherein the controller is configured to control the focusingon the subject when both the electronic device supports a half-pressshutter function and a user input that requests execution of thehalf-press shutter function is detected.
 16. The electronic device ofclaim 10, wherein the controller is configured to determine the at leastone focusing sensor to include both a direction measuring sensor thatdetermines a direction of a subject and a distance measuring sensor thatdetermines a distance to a subject.
 17. The electronic device of claim10, wherein the controller configured to detect a sound of a subjectusing a stereo microphone, and wherein the controller is configured tomeasure a distance to the subject using a triangulation scheme.
 18. Theelectronic device of claim 10, wherein, when a location of anothercommunication terminal is determined to be within an interval defined inadvance, the controller is configured to calculate the location of theother communication terminal so as to measure a direction and a distanceof the subject.
 19. The electronic device of claim 10, wherein, when theelectronic device is equipped with two photographing devices, thecontroller is configured to execute recognition of an eye pattern so asto set a Region Of Interest (ROI) based on a gaze of an eye of a personwho executes photographing.
 20. The electronic device of claim 10,wherein the sensor unit includes a plurality of sensors including atleast one of a touch sensor that recognizes a touch input, a proximitysensor that senses a proximity of an external object, a distancemeasuring sensor, an image sensor that collects an image, a motionrecognition sensor that recognizes a motion and a movement in athree-Dimensional (3D) space, a direction sensor that senses a directionand the like, and an acceleration sensor that detects a moving speed.21. The electronic device of claim 10, wherein the control unit isconfigured to detect feature information from among the collected sensorinformation, and wherein the feature information includes at least oneof an eye pattern recognition information indicating a direction atwhich a user gazes, sound localization information, symbol recognitioninformation, facial recognition information, and edge detectioninformation.